Recently, wind turbines have received increased attention as environmentally safe and relatively inexpensive alternative energy sources. With this growing interest, considerable efforts have been made to develop wind turbines and wind turbine plants that are reliable and efficient.
Generally, a wind turbine includes a rotor having multiple blades. The rotor is mounted to a housing or nacelle, which is positioned on top of a truss or tubular tower. Utility scale wind turbines (i.e., wind turbines designed to provide electrical power to a utility grid) can have large rotors (e.g., 30 or more meters in length). In addition, the wind turbines are typically mounted on towers that are at least 60 meters in height. Blades on these rotors transform wind energy into a rotational torque or force that drives one or more generators that may be rotationally coupled to the rotor through a gearbox. The gearbox steps up the inherently low rotational speed of the turbine rotor for the generator to efficiently convert mechanical energy to electrical energy, which is fed into a utility grid. In other wind turbine configurations, the gearbox may be omitted and the generator may be directly driven or driven through some other type of coupling.
Wind turbine placement optimization within a wind power plant has traditionally been performed with the single objective of maximizing energy production. For example, wind turbine can be placed at the locations within the wind plant having the highest winds based on a wind resource grid and then manually adjusting the turbine layout according to constraints such as exclusion zones and/or minimum spacing constraint. A wind resource grid can be generated using commercially available wind resource assessment or modeling software such as WindPro™ (available from EMD International A/S, Aalborg, Denmark), WindFarmer™ (available from Garrad Hassan, Bristol United Kingdom), or WindFarm™ (available form ReSoft Ltd., Banbury, United Kingdom). There are other design objectives of importance such as minimizing the cost of the wind plant, maximizing financial metrics, and minimizing noise. Typically, noise is a constraint whereas a certain noise level cannot be exceeded at one or more locations. To address cost, financial metrics, and noise constraints, commercial software such as WindPro™, WindFarmer™, or WindFarm™ offer analysis modules that can be used to manually adjust the turbine layout as desired. Therefore, the process of optimizing a turbine layout is iterative and manual. To reduce the manual or trial and error component of optimizing a turbine layout, commercially available wind resource assessment software have an optimization algorithm allowing for the automatic maximization of energy production for a fixed number of wind turbines and a particular wind turbine model/configuration. Noise constraints as well as areas for which wind turbines cannot be installed can be enforced. Additional analyses are needed before the turbine layout can be finalized. One of these additional analyses is the calculation of the mechanical loads on each wind turbine to ensure that they are within the design limits of the wind turbine model(s)/configuration(s) of interest. This task is almost exclusively performed by the wind turbine manufacturer because of their detailed design information and proprietary wind turbine modeling capabilities. Detailed knowledge of the design load margins (site specific loads-design loads) allows the minimization of these load margins, which in turn can yield additional energy capture. Currently, no known method available provides multi-disciplinary optimization capabilities for multiple criteria and constraints that directly include the assessment of mechanical loads.
Therefore, what is needed is a multi-disciplinary method for determining wind turbine placement within a wind power plant that efficiently provides the desired plant design and operational goals according to multiple criteria and constraints including mechanical loads analysis to obtain detailed design load margins.